In recent years, as a wireless data communication technique, a wireless LAN (Local Area Network) system of IEEE (The Institute of Electrical and Electronics Engineers) 802.11 standard has been considered as useful. Since the wireless LAN of the IEEE 802.11 standard has no directivity and radially transmits wireless waves, connection among apparatuses can be made over a wide range.
The IEEE 802.11 standard includes the IEEE 802.11a scheme which uses a 5 GHz bandwidth and allows data transfer at the maximum speed of 54 Mbps and the IEEE 802.11b scheme which uses a 2.4 GHz bandwidth and allows data transfer at the maximum speed of 11 Mbps.
In a communication system with strong directivity like those according to the IrDA (InfraRed Data Association) and the like, it is necessary to appropriately oppose apparatuses to be connected to specify targets for which communication is established. In the wireless LAN of the IEEE 802.11 standard, however, such positional limitation is not required.
Connection patterns of the wireless LAN of the IEEE 802.11 standard include two types, that is, an Infrastructure mode (one-to-many communication) which is a network formation in which stations, for example general-purpose personal computers or the like, are connected to an access point serving as a relay, and an Ad hoc mode (one-to-one communication) which is a network formation among stations.
A range in which one access point can communicate with a station is referred to as a basic service area (hereinafter referred to also as a BSA). Since a station moves as a user moves, communication may become impossible when a station goes out of the basic service area. Thus, to allow wireless communication to be used even when the station moves to the outside of the basic service area of an access point, a roaming technique has been realized in which a plurality of access points interconnected to each other through a wired LAN (a distributed system) are provided and a station can be connected seamlessly to a new access point in an area to which the station moves.
A communication-enabling range extended by providing a plurality of access points in this manner is called an extended service area (ESA). In this case, a station may receive signals from a plurality of access points, but in such a case, performs communication with an access point from which a stronger signal is received.
Conventionally, however, in wireless communication using the wireless LAN of the IEEE 802.11 standard and the like, when a network is formed by access points, stations and the like, there has been a problem that a user must set information inherent in the network to be formed in all the stations to result in poor usability.
In addition, when a station performs communication with another station, if a plurality of stations is present in a search range of the station, the station can detect a plurality of other stations present in the search range. Thus, there has been a problem that a user may connect a station held by him to a station other than a desired station.